The invention discloses an arrangement of building elements with connecting means, especially panels capable of separable connection to one another.
In this context, building elements are understood to mean panel-shaped building elements such as panel boards, floor boards, cladding boards, cladding strips especially for covering walls, ceilings or floors in buildings of every type. Building elements of this kind may comprise single or multiple-layer panels and/or strips made from wooden materials or on a wooden base (laminate), especially chipboard, medium density fibre board (MDF), high density fibre board (HDF), oriented strand board (OSB) and plywood panels, which may optionally be coated on one or both of the exterior surfaces. The coating or so-called useful surface maybe produced with synthetic material sheets, solid wood, veneers made from wood or synthetic material or paper etc. In the case of flooring panels, a decorative paper, for example with a natural wood design, intended to create the impression of a solid wooden panel, is widely known. Since flooring is placed under considerable stresses during normal use, the surface of the decorative paper is sealed with a hard, especially scratch-resistant and abrasion-resistant, overlay made, for example, from resin-soaked alpha-cellulose paper, and is therefore protected from scratches and dents. In particular, therefore, the invention relates to flooring boards or so-called panels, which consist of wooden materials and provide a relatively hard surface made from synthetic-material laminates.
Arrangements of building elements with separable connecting means are known from the prior art. The invention discloses a special type of design and manufacture for building elements and connecting means, which keeps the building elements in the optimum position relative to one another in the connected condition, but also allows the building elements to be separated from one another if required.
Known arrangements of building elements in the form of flooring panels provide at their lateral edges tongues and/or grooves, especially tongues which can snap into the grooves. Panels of this kind can be manufactured in a particularly economical manner, because only the generally relatively soft middle layer of the panels consisting particularly of wood needs to be processed specially in order to form the tongues and grooves acting as the locking means. The middle layer can also be described as the carrier layer or core. In the case of laminate flooring with a tongue milled into the middle layer, the middle layer generally consists of chipboard, MDF, HDF, hard-fibre board, solid wood or plywood material. These materials provide the disadvantage that, as described above, the tongues, in particular, are relatively soft and can therefore break either in their entirety or in part. A panel with a partially crushed tongue can only be introduced into the groove of another panel if the crush damage is specially treated prior to laying. This requires additional work when laying, and the strength of the connection between the interconnected panels is reduced.
The tongue which projects beyond at least one lateral edge of the panel is particularly susceptible to damage, because it can strike obstacles particularly hard in view of its small cross-section and the relatively heavy weight of the panel. This problem is encountered in manufacture and transportation as well as laying. The groove is also susceptible, because in the region of the groove, the panel provides a reduced wall thickness and strength. The exterior walls of the groove may even be thinner than the cross-section of the tongue.
Damaged tongues or tongues made from material permeable to water or capable of absorbing water also render the tongue and groove connection itself more permeable to water. Water spilled on the area of the connection can therefore penetrate more readily into the generally liquid-absorbing internal material layer (core) of the panel, which therefore swells and becomes visually unattractive. The moisture can also penetrate through the tongue and groove connection settling under the panels for a considerable time. This moisture cannot be observed or removed and, in the long-term, can therefore lead to consequential damage typical of moisture, especially mould, bacteria, efflorescence and staining.
EP 1 024 234 discloses panels of this kind with tongue and groove connections, wherein locking means for a snap-fastening are provided on the tongues and grooves. Since the tongues and grooves are milled from the core, which consists of HDF or MDF, in one piece with the locking means, the strength properties of the tongues and grooves are determined by the material properties of the core of the panel. In view of the strength of the connecting and locking means required for a secure connection, the core of the panel must therefore be harder, stronger, heavier and more expensive than is necessary, for example, for a floor covering.
U.S. Pat. No. 5,295,341 discloses panels in which the fastening means are connected to the edges of the panels in the form of strips, so that the materials used for the panels and the connecting means can each be optimised. In order to connect the connecting means to the panels, hook-shaped anchors are formed on the connecting strips, which engage with undercutting provided on the panels. An undercut geometry of this kind can only be manufactured at a considerable expense.
WO-A-00/20706 and WO-A-00/20705 disclose flooring panels which can be connected to one another via separate connecting profiles by moving the longitudinal edges horizontally towards one another or by lowering the longitudinal edges vertically. Accordingly, the locking means must lock on both sides, that is, with the longitudinal edges of two profiles to be connected. This increases manufacturing costs, because the separate connecting means must be attached to the longitudinal side of a profile in the factory. Otherwise, the work required on-site by the installer is increased, because, immediately before installation, the installer has to connect the connecting means first to one side and then to the other side of the panel to be connected. Accordingly, the connecting means are not firmly connected to the panel on both sides, thereby doubling the risk of accidental separation and rendering the connection less rigid and less strong. Moreover, additional processing stages must be carried out for each connection, namely, for two grooves and two tongues. Normally one groove and one tongue is sufficient for each connection.
The object of the present invention is therefore to provide an improved arrangement for building elements with connecting means, which removes the disadvantages named above.